Method for charging liquid products and volatile propellants into pressure-tight containers



July 27, 1954 D. M. MCBEAN 2,684,805

METHOD FOR CHARGING LIQUID PRODUCTS AND VOLATILE PROPELLANTS INTOPRESSURE-TIGHT CONTAINERS Filed Aug. 9, 1950 V /.17 TILE P/FOPfZZA/VTLIQUID PRODUCT J4 /5 VACl/l/M ?'74/V/f 0/59! gay 6 S 49 av- 97 ,3"; raw

C OlHPRES 5 E 0 19/? INVENTOR DOUGLAS M. McBEAN Mai/MM Patented July 27,1954 METHOD FOR CHARGING LIQUID PROD- UCTS AND VOLATILE PROPELLANTS INTOPRESSURE-TIGHT CONTAINERS Douglas M. McBean, R

to Carter Products, I

chester, N. Y., assignor 110., New York, N. Y., a

corporation of Maryland Application August 9, 1950, Serial No. 178,522

Claims.

This invention relates to the filling of compositions comprising liquidproducts and volatile propellants into pressure-tight packagingcontainers, and more particularly to a method in which the compositionis maintained under considerable superatmospheric pressure during thefilling operation so as to maintain the volatile propellant in liquidphase during filling and in the filled container. The invention alsoincludes improved apparatus by which the method may be carried out.

Pressure-tight cans or packaging containers having valve controlledoutlets may be filled or charged with compositions comprising a volatilepropellant and a liquid product by introducing these ingredients under asuper-atmospheric pressure sufficient to maintain the propellant inliquid phase. By a volatile propellant, I mean a compound having a vaporpressure considerably above atmospheric pressure at normal roomtemperatures. Such compositions are desirably charged into the packagingcontainers under suificient pressure to maintain the volatile propellantin liquid phase, both during the charging operation and in the chargedcontainer. If not maintained under such pressure, the propellant wouldvaporize and so expand to such a volume that only a small quantity ofthe composition could be charged into the container. One methodinvolving the charging of such compositions into packaging containersunder pressure is disclosed in my Patent No. 2,641,399, granted June 9,1953, on a copending application.

When a composition of the type described is charged under pressureinto acontainer through a valve controlled container opening, the chargingpassages leading to the container opening are, at the conclusion of thecharging operation, filled with a mixture of the liquid preparation andthe volatile propellant under considerable superatmospheric pressure.When the filled container is disconnected from the charging passages,this mixture is forcibly discharged from the charging passages by itspressure and by the flashing or sudden vaporization of the volatilepropellant constituent thereof upon release of pressure therefrom. Thethus discharged composition flows over the filled container beingdisconnected from the charging passage and over the container supportingand conveying means, necessitating subsequent cleansing of the filledcontainer and frequent cleansing of the container supporting andconveying mechanism. This discharge of composition from the chargingpassages is particularly undesirable where the liquid prodnot comprisesa foam producing material, such as an aqueous soap solution, which isexpanded into a lather or foam by vaporization of the volatilepropellant when the composition is released to atmospheric pressure.Lather producing compositions of this type are disclosed in my PatentNo. 2,655,480, granted October 13, 1953, on a copending application.

It is the primary object of the present invention to provide an improvedmethod for charging a liquid product and a volatile propellant into apressure-tight packaging container through a valve controlled opening inthe container without permitting vaporization of the volatile propellantso charged and without the discharge of the filled materials from thecharging passage when the filled container is disconnected therefrom. Afurther object of the invention is the provision of improved apparatusby means of which the improved method can be carried out, In general,the method of the invention includes the steps of charging the containerthrough an opening with the volatile propellant and liquid product undersufficient superatmospheric pressure to prevent substantial vaporizationof the propellant, closing the container opening while the container isconnected to the charging passage, then while the container is soconnected, connecting the charging passage to a chamber maintained underpartial vacuum whereby the volatile propellant and liquid productremaining in the charging passage is withdrawn therefrom and thepressure therein is reduced to a subatmospheric value, and finallydisconnecting the container from the charging passage.

In describing the invention in detail, reference will be made to theaccompanying drawing, in which the single figure illustrates apparatusembodying the invention and by means of which the method of theinvention may be carried out.

As illustrated in the drawing, the pressure tight packaging containercomprises a can C having a top wall I with a central tube 2 sealedtherein and forming the can opening. A suitable valve mechanism isprovided and as here illustrated comprises an inturned flange 3 at theinner end of the tube 2, which forms a valve seat for cooperation with avalve plug 4 carried by a stem 5 extending through the tube 2. The stem5 is biased to move the plug 4 to valve closing position by a spring 6compressed between the inner face of the flange 3 and a stop I struckfrom the stem 5. Depression of the outwardly extending end of the stem 5opens the valve and upon release of the stem the spring 6 closes it.

A syphon tube 8 may be fitted over the inner end of the valve tube 2 andextended to a point near the bottom of the can C to insure substantiallycomplete expulsion of the can contents when the can is in use.

The can C illustrates one of a series of pressuretight valve equippedpackaging containers that are successively connected in pressure-tightrelation with a charging passage and there charged with volatilepropellant and liquid product under superatmospheric pressure inaccordance with the method of the invention. As shown, a block 8 isprovided with a charging passage comprising a duct is and a connectedduct H. The duct It extends vertically in the block and its lower endforms a charging opening provided with suitable means for effecting apressure-tight coupling or connection with the can opening comprisingthe upper end of the tube 2. As here illustrated, the coupling mechanismcomprises a body it secured to the block 9 at the end of the duct ithaving a central opening l3 extending therethrough in line with the ductit. An annular channel M in the lower face of the body l2 slidablycarries a compression member E5, the flanged lower end of which liesbeneath the lower end of a compressible resilient gasket 15 of rubber orother suitable material. The central opening H of the gasket i6 is of asize to receive the can tube 2 and pressure of the top wall 1 of the canC on the compression member it expands the gasket l6 so that it forms apressure-tight connection between the can tube 2 and the opening l3leading to the block duct l2. The can is pre erably lifted to connectedposition on a vertically movable platform 18, which forces the canupward to effect the described connection and which may be lowered todisconnect the can from the charging passage.

A can valve operating rod i9 is provided in the duct It and as hereillustrated comprises a simple rod spaced concentrically from the wallof the duct and extending out of the top of the block 9 through apressure-tight packing joint 28. When the rod 59 is depressed, its lowerend engages the upper end of the valve stem ES and so opens the valve,and when the rod it is lifted, stem is released and the valve closed.The rod 59 may be operated by any suitable mechanism, such for exampleas that disclosed in my copending application Serial No. 147,588, filedMarch 4;, 1950.

A. source of vacuum, here illustrated as a vacuum. reservoir 2|connected to be evacuated by a vacuum pump 22, is connected to the ductll through a conduit 23 controlled by a valve E l. A vacuum surge tank25 is connected to the vacuum reservoir through a conduit 2% having avalve it therein. The vacuum surge tank 25 has drain is provided with avalve 29. A conduit 32 provided with a valve 3i connects the vacuumsurge tank 25 with the duct II.

Suitable means are provided to supply volatile propellant and a liquidproduct under superat mospheric pressure to the ducts it and ll thatform the container charging passage. As here shown, a propellant conduit32 provided with a control valve 33 is connected to the propellantcylinder Ed by a propellant metering device, generally designated P. Thedevice P compri es essentially a power cylinder 35 carrying a piston 35connected by a rod 31 to a piston 36 in a propellant cylinder 34.Compressed air or other motive fluid from a suitable source isalternatively admitted to and vented from opposite ends of the powercylinder 35 under control of the valves 39 and 4-8 in order toreciprocate the connected pistons 36 and 38 and so force successivemeasured charges of propellant under superatmospheric pressure from thecylinder 34 into successive cans to be filled. Volatile propellant inliquid phase is supplied to the propellant cylinder 34 from a supplytank ll through a conduit 42 provided with a check valve G3.

The means for supplying a liquid product which may be a foam or latherproducing liquid, such as an aqueous soap solution, is here illustratedas a metering device S, including a product cylinder i l connected tothe block duct H by a conduit 66 controlled by a valve "5. A productsupply tank i i is connected to the product cylinder til through aconduit 55 having a check valve 5? therein. A piston 48 in the productcylder Lid is connected by a rod 59 to a power cylinder pistonCompressed air or other motive fluid is admitted to and vented from thepower cylinder 51 by means of a valve 52 whereby the connected pistons5.8 and 5d are reciprocated to deliver successive measured charges ofliquid product under superatmospheric pressure to the successive cans tobe filled. The pressure under which the volatile propellant and theliquid prodnot are charged by means of the metering devices P and S issuiiiciently high to maintain the volatile propellant in liquid phase atthe prevailing temperatures.

In carrying out my improved method by the apparatus described, the can(3 is connected in pressure-tight relation to the charging passagecomprising the ducts it and l i and the can valve is opened bydepressing the rod Ill. The can may then be evacuated opening the valve24 for a suitable interval. Then measured quantities of liquid productand volatile propellant in liquid phase are charged into the can byopening the valves 33 and ti and operating the metering devices S and P.The pressure under which the product and propellant are charged into thecan is maintained at a high superatmospheric value substantially abovethe vapor pressure of the volatile propellant at the preva' gtemperature, so that no substantial vaporization of the propellantoccurs during the charging operation.

At the conclusion of the charging operation, the can C and the chargingpassage comprising the ducts l5 and ii are filled with liquid productand some volatile propellant in liquid phase and are under considerablesuperatmospheric pressure. At this point. the can valve is closed bylifting the rod is, and then the charging passage is connected to thevacuum surge tank by opening the valve 3!. This suddenly reduces thepressure in the charging passage, causing flashing or suddenvaporization of any volatile propellant contained therein, which drawssome of the liquid product contained in the charging passage through theconduit Si) into the vacuum surge tank 25. By this operation, not onlyis the charging passage cleared of some of the liquid product andvolatile propellant therein, but in addition the pressure in thecharging passage is reduced to a value somewhat below atmosphericpressure. The can C is then disconnected from the charging passage andthe remainder of the liquid product in the charging passage is forcedinto the tank 25 by atmospheric pressure. Due to the vacuum surgeoperation described, no liquid product or volatile propellant isdischarged from the charging passage when the can is disconnectedtherefrom.

The vacuum surge tank 25' may be maintained at a suitablesub-atmospheric pressure by opening the valve 21. Liquid product may beperiodically drawn from the vacuum surge tank 25 by closing the valve 2!and the valve 3| and opening the drain valve 29.

I claim:

1. The method of charging a liquid product and a volatile propellantinto a pressure-tight packaging container having a valve controlledopening which comprises eifecting a pressuretight connection between thecontainer opening and a charging passage, opening the container valve,introducing liquid product and volatile propellant to the containerthrough the charging passage under superatmospheric pressure, closing thcontainer valve, thereafter, but before breaking the pressure-tightconnection, connecting the charging passage to a chamber maintained atsub-atmospheric pressure whereby volatile propellant and liquid productis withdrawn from the charging passage, and then disconnecting thecontainer opening from the charging passage.

2. The method of charging a liquid product and a volatile propellantinto a pressure-tight can having a valve controlled opening whichcomprises connecting the can opening to a charging passage, opening thecan valve, introducing measured charges of liquid product and a volatilepropellant to the can through the charging passage undersuperatmospheric pressure above the vapor pressure of the propellant atthe prevailing temperature, closing the can valve, thereafter, butbefore breaking the pressure-tight connection, subjecting the chargingpassage to sub-atmospheric pressure whereby volatile propellant andliquid product remaining in the charging passage are withdrawn therefromand the pressure in such passage is reduced to a sub-atmospheric value,and then disconnecting the can opening from the charging passage.

3. In a method of charging a liquid product and a volatile propellantinto a pressure-tight container having a valve controlled opening inwhich the product and the propellant are introduced into the containerthrough a charging passage to which the container is releasablyconnected under a superatmospheric pressure above the vapor pressure ofthe propellant at the prevailing temperature, the improvement whichcomprises closing the container valve after the product and propellanthave been charged into the container and before disconnecting thecontainer from the charging passage, then subjecting the chargingpassage to a subatmospheric pressure whereby volatile propellant andliquid product remaining in the charging passage is withdrawn therefromand the pressure in such passage is reduced to a subatmospheric valueand then disconnecting the container from the charging passage.

4. In a method of charging a liquid product and a volatile propellantinto a pressure-tight container having a valve controlled opening inwhich the product and the propellant are introduced into the containerthrough a charging passage to which the container is releasablyconnected under a superatmospheric pressure above the vapor pressure ofthe propellant at the prevailing temperature, the improvement whichcomprises closing the container valve after the product and propellanthave been charged into the container and before disconnecting thecontainer from the charging passage, then connecting the chargingpassage to a chamber maintained at a subatmospheric pressure wherebyvolatile propellant and liquid product remaining in the charging passageare withdrawn therefrom, and then disconnecting the container from thecharging passage.

5. Apparatus for charging a liquid product and a volatile propellantinto a pressure-tight packaging container having an opening controlledby a valve comprising a charging passage having a container chargingopening, means for releasably connecting a container opening inpressure-tight relation to said charging passage opening, means forforcing a volatile propellant and a liquid product through said chargingpassage and into said container under superatmospheric pressure, amovable valve operating rod in said charging passage for operating thecontainer opening valve, a source of vacuum, a vacuum surge tank, meansfor connecting said surge tank to said source of vacuum, means forselectively connecting said surge tank to said charging passage, andmeans for draining accumulated liquid product and volatile propellantfrom said vacuum surge tank.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,427,429 Waite et a1 Sept. 16, 1947 2,505,799 Smith May 2,1950 2,518,064 Rapisarda Aug. 8, 1950 2,523,560 Cozzoli Sept. 26, 1950FOREIGN PATENTS Number Country Date 468,224 Great Britain June 30, 1937

